Anatomy and Pathophysiology

As a result of their unique anatomy and physiology, children are more likely than adults to experience acute airway obstruction. According to Poiseuille’s law, resistance is proportional to the fourth power of the radius with laminar flow and estimated to be proportional to the fifth power of the radius with turbulent flow, as in cases of stridor.8(See Figure 1.) For this reason, stridor may present only when a child is crying or agitated and turbulent flow through the airway is present.